Roofing materials



United States atent C) ROOFING MATERIALS Harry Fleeman, 48 Leeds Road, Kippax, Leeds, York County, England Filed Aug. 17, 1964, Ser. No. 390,774 Claims priority, application Great Britain, Sept. 24, 1963,

4 Claims. (Cl. 161-112) This invention relates to new or improved roofing felts, and similar coverings and floor coverings in sheet form.

It is well known that roof structures, particularly those made of concrete and modern insulating materials, naturally contain a certain amount of moisture, in addition to that adsorbed in inclement weather during construction. When the roof is subsequently covered with a waterproof material such as asphalt or rooting felt, this moisture can no longer dry out without hinderance, from the upper surfaces of the roof deck.

Variations of temperature on the exterior of the roof draw moisture up to the surface of the deck. Being unable to pass through the waterproof covering of felt, asphalt, or other covering, it accumulates in this position between the roof deck and the covering. If it remains there, heat to the roof exterior surface, can cause this moisture to evaporate. The evaporation is a process of expansion and unless the vapour can escape, it lifts and distorts the felt or other covering. Repeated lifting and distortion may eventually crack the covering.

Another problem which this trapped moisture can create is caused when it is unable to escape sufficiently as a vapour. As a condensed liquid, this moisture finds crevices in the roof deck through which it drains back to the ceilings below, or runs down the sides of supporting walls. This moisture also becomes alkaline because of the concrete, and as such it attacks the bitumens of the roof covering. The result is that this water which runs down the walls or falls from the ceilings, is dark coloured and staining.

Various methods are adopted to remove this moisture. Ventilators are put through the roof covering, rough sand is spread on the roof deck before the felt is laid, or the felt may only be stuck down at intervals. Another method is to make the felt with a coarse gravel facing. A further method is to stick fluted corrugated paper to the roof deck using the flutes as venting ducts and then sticking further sheet material to the top of the flutes.

These troubles caused by entrapped moisture can lbe prevented by using a felt or similar covering made with a facing which has a raised form, as for example, dimpled, globular, noduled, uted, reeded, grooved, or other relief form. With this face placed on to the roof deck, the felt will rest on the relief pattern which must be such as to allow the moisture vapour to pass between the nodules or protuberances of the embossing and the roof deck or oor to escape through the ventilators or drain holes.

The facing of such a felt or covering would need to be permanently embossed to be effective. It would be insuicient to merely emboss the facing of an ordinary pliable and plastic roof covering because the embossing would collapse under warmth or pressure. It is therefore necessary to make the felt from a permanently embossed sheet of suitable material which can be coated with a waterproofing medium such as bitumen, tar, mastic, rubber and the like, to become a single integral sheet with an ambossed face. The coating will fill in the embossing, so that the relief pattern of the sheet which rest on the roof deck, will be hard, solid and permanent. The back of the sheet, or the upper surface, will present a flat waterproof surface. To this at upper surface will be stuck the additional layers of felt as laid in the normal built-up roof.

It has previously been pointed out that the roof cover- Patented Feb-20, 1968 ing can be chemically attacked because of the salts absorbed from the roof deck. Because of the very presence of water under the covering, it can also be appreciated that the basic embossed sheet as it rests on the deck, should not be seriously weakened or affected by contact with water, contaminated or otherwise.

It will also be appreciated that this embossed sheet must not collapse during coating, and must be rigid enough to withstand the operation. As bitumen and tars are usually applied hot, this means that when coated with bitumen the embossing must not collapse under the heat. This invention now proposes that roofing felts and coverings be made from an embossed base which will not collapse under heat or moisture. One such material consists of a lamination of polythene or similar thermo-plastic plastic sheets between outer layers of paper. When this lamination is embossed under heat, the plastic is permanently formed into a relief pattern as previously described. The paper at each side of the plastic is heat sealed to the plastic during the embossing. Such an embossed lamination will never lose its form if wet because the plastic supports the wet paper. During coating with hot bitumen or tar, the embossed plastic will not collapse under the heat because it is supported by the paper. The paper side which goes to the roof deck can be treated to make it rot proof but for ordinary purposes, a pureA paper is adequately resistant to the alkalis. The plastics such as polythene or P.V.C. are highly resistant to all chemicals likely -to be encountered and present a waterproof layer to prevent the rising Water contacting any bitumen coatings. Thus, with a roof covering made according to the invention there is no danger of the rising water becoming stained, or rotting anything, which could also cause odours. It will be further appreciated that such an inert base material is also resistant to biological attack.

In the accompanying drawing:

FIG. 1 shows the relief form on the underside of the felt or covering in enlarged form.

FIG. 2 shows a cross section through the line A.A. 1 is the embossed lamination of thermo-plastic sheeting between sheets of paper. This has become integrally united with the coating of waterproong substance 2. 3 is the roof deck or floor on which the nodules of the covering rest. Between the raised nodules of the relief embossing are the continuous Ventilating cavities 4.

A roof covering made in the manner described has improved waterproof qualities because of the incorporation of a sheet of waterproof plastic, but additionally, the elasticity and ductility of the plastic, improves the quality of the covering because it imparts these qualities to the finished material.

A further aspect of the invention results from the fact that the process of coating one side of the embossed sheet enables a further flat sheet of waterproof material to be incorporated. After the bitumen, tar or like substance is coated on to the embossed sheet, because of its adhesive nature during manufacture, another sheet of flat roong felt or other covering pressed to it, will become rmly bonded. The process can, of course, be performed in the opposite manner during the manufacture of ordinary roofing felts, by pressing the embossed sheet to the saturated sheet of felt.

It is now further proposed that the embossed sheet. should be narrower than the at sheet of felt. If they are combined with one edge of each together, there will be a strip of ilat sheet at the other edge without embossing. When laying this material on a roof, this flat edge can be stuck down over the adjoining sheet to form a continuous waterproof membrane.

In the case of the coated embossed sheet material, the sheet may be pierced or punched with holes at regular intervals before or after coating. When this sheet is rolled out on a roof deck, bitumen spread over its flat surface, for adhesion of the next layer of felt, will pass through these holes, to stick to the deck and anchor the sheets to it. In the case of the combined embossed sheet and iiat sheet, the holes may best be made after the sheets are combined.

It will also be realized that the same problems as those previously explained and associated with moisture rising from roof decks, can occur with floors, This invention can, therefore, be utilized in relation to floor coverings such as linoleum, rubber, plastic and similar materials, whereby the base of the material is made to incorporate an embossed or relief formation in the manner previously described in relation to room materials.

The claims dening the invention are as follows:

1. A sheet covering comprising a 'base consisting of a lamination of a thermo-plastic plastic sheet between sheets of paper `bonded together and embossed under heat, and then coated on one side with bitumen, tar or rubber which unites with the bonded sheet to make a ductile covering with an embossed base that is not affected by heat or water.

2. A sheet covering comprising a base consisting of a lamination of thermo-plastic plastic sheet between sheets of paper, bonded together and embossed under heat, and then coated on one side with bitumen, tar or rubber which unites with the bonded sheet to make a ductile covering with an embossed base that is not affected by heat or Water, through which holes are punched at intervals.

3. A sheet covering comprising a base consisting of a lamination of a thermo-plastic plastic sheet between sheets of paper, bonded together and embossed under heat, and then coated on one side with bitumen, tar or rubber which during manufacture when it is in an adhesive state, is used as a bonding material to unite the embossed sheet to a sheet of at rooting felt or other covering of wider width, one edge of each sheet being together.

4. A sheet covering comprising a base consisting of a lamination of a thermo-plastic plastic sheet between sheets of paper bonded together and embossed under heat, and thencoated on one side with bitumen, tar or rubber which during manufacture when it is in an adhesive state, is used as a bonding material to unite the embossed sheet to a sheet of flat roofing felt or other covering of wider width, one edge of each sheet being together, the combined sheets then being punched with holes at intervals.

References Cited UNITED STATES PATENTS 271,075 1/1883 Janks 161--130 315,503 4/1885 Howes 161-130 347,763 8/1886 Baker 161-130 2,042,470 6/1936 Kieffer 161-130 2,275,575 3/1942 Vrooman 161-130 1,902,872 3/1933 Long 161-130 1,193,013 8/1916 Grant 161--120 1,409,768 3/1922 Perry 161-121 DOUGLAS I. DRUMMOND, Primary Examiner.

EARL M. BERGERT, Examiner. 

1. A SHEET COVERING COMPRISING A BASE CONSISTING OF A LAMINATION OF A THERMO-PLASTIC PLASTIC SHEET BETWEEN SHEETS OF PAPER BONDED TOGETHER AND EMBOSSED UNDER HEAT, AND THEN COATED ON ONE SIDE WITH BITUMEN, TAR OR RUBBER WHICH 